As far as I know, they (IDL) had 8,000 Midleton wooden boxes left over when they moved to the new packaging for the 2017 release. They decided to use these boxes to create an 'old packaging' 2017 which they only released in to travel retail (duty free shops).

I think 2008 had an issue of around 47,000 bottles so 8,000 old pack 2017s is going be much rarer I suppose? FYI, if you keep an eye on the serial numbers of the MVR (on the front label, down to the bottom right) you see for sale on the auction sites you'll get an idea of how many bottles were issued (over time that is, you'd nearly need to follow it for a while to get a fair picture). I have no idea how many of the 2017 new packaging are being issued...